Comparison of the effect of dydrogesterone and natural micronized progesterone for luteal‐phase support in assisted reproductive technology cycles: A single‐blind randomized clinical trial study

Abstract Background and Aims One of the causes of preterm labor and recurrent abortion is progesterone deficiency in the luteal phase. The aim of the study was a comparison of the effect of oral dydrogesterone and vaginal progesterone for luteal‐phase support (LPS) in assisted reproductive technology cycles (ART). Methods This randomized clinical control trial study was conducted on 207 infertile women. Samples were randomly divided into two groups. The first group received a natural micronized vaginal progesterone (MVP) of 400 mg once daily and the second group received dydrogesterone (Duphestone) 20 mg twice daily. Then chemical pregnancy, abortion, and live births were compared in two groups. Results The results of the study showed that the vaginal form of the drug could increase the chance of pregnancy (positive β‐human chorionic gonadotropin) versus the oral form. According to the results of multiple logistic regression analysis after adjusting for other variables, the live birth rate in the vaginal group was more than five times that of the oral group (odds ratio = 5.07; 95% confidence interval = 1.24–20.65; p = 0.023). Conclusion The vaginal form of the progesterone could increase the chance of pregnancy and the outcome of fertility (live birth). Thus, vaginal progesterone is effective for LPS in women undergoing fresh embryo transfer.

Recurrent miscarriages and preterm labor cause many perinatal deaths in the community and their prevention is a major step in the health of mother and infant. 1 They are one of the most common problems in pregnancy. 2One of the causes is progesterone deficiency in the luteal phase which can be reduced by administration of progesterone with the luteal-phase support (LPS). 3 Some researchers have stated that progesterone has a clear impact on high-risk pregnancies and the rate of preterm labor with the help of progesterone is decreased in these pregnancies but it is mostly used in reproductive technology cycles (ART). 1,4 has been suggested that dydrogesterone can lead to virilization when used at high doses, but this side effect is not seen at usual doses. 5The pharmacological effects of the progesterone supplements usually begin on the day of oocyte retrieval or at the time of embryo transfer (ET). 6Although estradiol supplement is commonly prescribed, there is no evidence to suggest that the outcomes of its use improve the outcome compared to those of using progesterone supplement alone. 7e results of one study showed that there was no difference in fertility outcomes between two groups of dydrogesterone and micronized vaginal, but the serum progesterone level was significantly lower in the dydrogesterone group.However, the successful fertility was higher in oral type. 8A meta-analysis study concluded that the results of using oral dydrogesterone were similar to using vaginal progesterone capsules in a live birth. 9In a study, fertility rates were significantly higher in oral progesterone than vaginal progesterone and were higher in the group taking the combined oral and vaginal types compared to the group taking each type alone. 10Ozer and colleagues demonstrated that vaginal progesterone is as effective as oral dydrogesterone for LPS in women undergoing in vitro fertilization (IVF). 11e natural micronized vaginal progesterone (MVP) has complications such as vaginal bleeding, spotting, or local irritation.Also, the form of intramuscular injection cannot be tolerated due to pain at the injection site and abscess.The use of the dydrogesterone is easy, accessible, and affordable. 12Progesterone is responsible for many morphological and biochemical changes in the endometrium, which optimize the endometrial differentiation in close synchronization with embryo differentiation.Progesterone is mainly used to prepare the endometrium for fresh ET cycles after IVF and in frozen embryo transfer (FET) as hormone replacement therapy (HRT) or naturally supplemented cycles. 13The MVP is an effective option to support the luteal phase.Because it makes it possible to optimize the effect on the endometrium with minimal systemic exposure. 14successful ART cycles impose costly treatment and psychological stress on couples.Since one of the recommended drugs in ART is the administration of progesterone for LPS, the results of this study can be an important step in improving infertility treatment in the country.Therefore, this study was conducted in ART-treated patients referred to Fatima Al-Zahra Fertility and Infertility Center in Babol City.  of the study included the pregnancy check using the human chorionic gonadotropin (hCG) test of the woman's blood, which was performed once a week after the transfer of the embryo to the patient.The secondary outcome includes the examination of premature birth at times every 2 weeks from the 20th week of pregnancy with a patient visit and recording uterine contractions, the rate of live births at times every 2 weeks from the 28th week of pregnancy with a patient visit and registering the birth of a baby, and the abortion recording 6 weeks after intervention with ultrasound and a pregnancy test.

| Statistical analysis
The data was analyzed using SPSS (

| RESULTS
The present study evaluated 264 women referred to the Fatima Al-Zahra fertility and infertility health research center, among whom 54 cases were excluded from this study due to improper endometrial thickness (n = 32), inappropriate BMI (n = 7), inappropriate age ranges (n = 10), ovarian hyperstimulation syndrome (OHSS) (n = 2), and lack of embryo formation (n = 3), respectively.Therefore, 105 people were included in the study in each of the two vaginal and oral groups.
Finally, we had two lost follow-ups in the oral progesterone group and one lost follow-up in the vaginal progesterone group (Figure 1).
Mean variables of age, BMI, endometrial thickness, and duration of infertility were shown similar in these two groups.The embryo number in the vaginal and oral groups was 3.85 ± 1.87 and 4.20 ± 1.92, respectively, and there was no significant difference in the two groups.Also, characteristics of the history of previous pregnancy including, gravidity, abortion, parity, and live birth were compared between two groups.There was no significant difference between groups after homogenizing the variables (Table 1).
The vaginal form of the drug could increase the chance of chemical pregnancy (positive β-human chorionic gonadotropin [β-hCG]) versus the oral form but this difference was not significant (p = 0.285).In the initial analysis, the rate of abortion in the oral group was higher than in the vaginal group and the rate of live birth was less than in the vaginal group, which was statistically significant between the two groups (p = 0.010 and p = 0.001, respectively) (Table 2).Preterm labor did not occur in any of the two study groups.
The odds ratio (OR) of outcomes was calculated in the vaginal versus oral groups using a logistic regression model.The unadjusted OR was first calculated; next, the effects of other associated variables including BMI, endometrial thickness, and fertility behaviors (gravida, para, live birth) were controlled; and then, the adjusted OR was calculated.In interpreting the regression model for evaluating the β-hCG and abortion variables, the unadjusted and adjusted were not significant.According to the results of multiple logistic regression analysis unadjusted and adjusted for other variables, the live birth rate in the vaginal group was more than five times that of the oral group (OR = 5.29; 95% CI = 1.47-19.03;p = 0.011 and OR = 5.07; 95% CI = 1.24-20.65;p = 0.023, respectively) (Table 3).

| DISCUSSION
In the current study, the effect of two therapeutic modalities of dydrogesterone and MVP for LPS in ART cycles was compared in women referred to the Fatima Al-zahra Fertility and Infertility Center.The results indicated that the use of both vaginal and oral progesterone had an effect on the outcome of ART cycles, but the vaginal form of the drug could increase the chance of pregnancy (positive β-hCG) more than the oral form.The LPS in ART cycles can be started after hCG administration, on the day of oocyte retrieval or the day of ET.The LPS usually begins on the day of oocyte retrieval with the administration of one form of the progesterone medication.In our study line, Salehpour and colleagues reported that clinical pregnancy was higher in vaginal progesterone than oral dydrogesterone, but the difference between the two drugs was not significant.In addition, the abortion rate was similar in both drugs.Also, there were no significant differences between the two drugs in the endometrial thickness, luteal-phase length, number of antral follicles, number of embryos, and number of metaphase-II oocytes.Therefore, vaginal progesterone was as effective as oral dydrogesterone for LPS. 16 one study, researchers reported that in the two groups of injectable progesterone and oral progesterone combined with vaginal gel, the fertility rate and pregnancy outcome were similar.In the ongoing study, β-hCG positive was higher in the vaginal form. 17In the meta-analysis study, Barbosa and colleagues retrieved 376 records and evaluated the positive effect of increased progesterone levels for LPS.
Sufficient quality evidence suggested that the oral dydrogesterone had, at least, similar results compared to vaginal progesterone capsules in live birth (risk ratio [RR] = 1.08, 95% CI = 0.92-1.26)and clinical pregnancy rates (RR = 1.10, 95% CI = 0.95-1.27).According to the obtained results, the effect of oral and vaginal forms has been the same in two groups; the dydrogesterone is a good option for choosing the medication and it should be on the basis of side effects and cost. 9ntrary to the results of our study, Saharkhiz and colleagues conducted a study on women undergone ICSI-ET and concluded that there was no difference in fertility outcomes between dydrogesterone and control groups.Although the serum progesterone level was significantly lower in recipients of oral type than in micronized vaginal one, the results of successful fertility were higher in the oral form with 20.66 ± 18.09 compared to 13.62 ± 13.83 (p = 0.001). 8teal-phase support is a complex and controversial issue in the field of reproductive management.In one study, the chemical and clinical pregnancy rate was higher in the vaginal progesterone group compared to the subcutaneous injection group. 18All routes of administration of progesterone, regardless of the route of administration, cause an increase in serum progesterone levels.Progesterone concentration in the endometrial tissue is higher after vaginal administration than after intramuscular or subcutaneous administration, despite lower serum levels.The MVP causes a better intratissue concentration for decidualization of the endometrium, thus increasing the chance of pregnancy. 13An alternative option to deal with cases of insufficient progesterone levels in FET involves doubling the number of daily doses in ART cycles with a sustained-release vaginal gel. 18Vaginal progesterone causes the regulation of inflammatory cytokines, natural killer (NK) cells, and arachidonic acid in the uterus, and causes more successful implantation. 19The results of our study showed that in the initial analysis, the rate of abortion in the oral group was higher than in the vaginal group and the rate of live birth was less than in the vaginal group. 20The aim of Griesinger and colleagues' study was to compare dydrogesterone and MVP gel for LPS F I G U R E 1 CONSORT flowchart.BMI, body mass index; OHSS, ovarian hyperstimulation syndrome.
in IVF.Their findings showed that the rates of pregnancy and live birth were higher in the dydrogesterone group than progesterone gel group.Moreover, the dydrogesterone with good tolerability had similar safety properties to MVP gels. 21Another study done by Turgal and colleagues measured the volume of the placenta and gestational sac in pregnant women threatened by miscarriage.They demonstrated that the placental volume was significantly higher in the group taking MVP than control group receiving no treatment, and the mean difference in gestational sac volume was not statistically significant in two groups. 22Hence, the positive effect of progesterone on LPS is conclusive in their study considering the comparison of the group taking progesterone with control group (no treatment).
The results of our study showed that the live birth rate in the vaginal group was more than five times of the oral group.The results of one study showed that vaginal progesterone was more effective in pregnancy outcomes. 23In another study, the simultaneous use of dydrogesterone and MVP gel was associated with higher clinical pregnancy and live birth rates than the use of micronized progesterone gel alone. 24Tomic and colleagues compared the oral dydrogesterone and MVP gel for LPS in women undergoing ART and found that the early administration of progesterone gel within the first 24 h of oocyte retrieval may lead to reduced pregnancy rates due to the early endometrial progression in a group receiving MVP gel. 25The role of progesterone in early pregnancy is to balance the mother's immune system, suppress the mother's immune system to some extent, prevent rejection of the fetus, and maintain the pregnancy.In fact, progesterone is essential for successful implantation.
The results of our study showed that preterm labor did not occur in any of the two study groups.Also, other studies reported that progesterone prevents preterm labor. 1,4We should mention that more negative results in the oral progesterone group may be because the oral form is metabolized in the liver, and in addition to side effects, it may not produce a proper and regular blood level.The vaginal form of progesterone is fast-acting and directly affects the uterus and can create a suitable blood concentration.
Our study has both strengths and limitations.The presence of homogeneous samples in the groups was one of the strengths of the present study, but one of the limitations was that there was an insufficient supply of embryo culture medium due to the sanctions.

| CONCLUSION
In conclusion, the results of the current study suggested that the MVP could increase the chance of pregnancy and the outcome of fertility (live birth).Thus, vaginal progesterone is effective for LPS support in women undergoing ET.
T A B L E 1 Demographic-fertility characteristics in study groups.The data were assessed using logistic regression.

2 | MATERIALS AND METHODS 2 . 1 |
Study design and participantsThis randomized clinical trial study was performed on infertile women undergone microinjection, referred to the Fatima Al-Zahra fertility and infertility health research center of Babol University of Medical Sciences from October 2018 to February 2020.It was registered in the Iranian Clinical Trial registry under the number IRCT20170205032406N2. Inclusion criteria included infertile women aged 20-40 years, body mass index (BMI) 18-30, endometrial thickness 7-14 mm.Exclusion criteria included patients with abnormal prolactin and thyroid tests and decreased ovarian reserve (baseline follicle-stimulating hormone > 10).The sample size was calculated in Saharkhiz and colleagues' study. 8With a 95% confidence interval (CI) and 10% drop, 105 people in each group and 210 people were examined in two groups based on the following formula.Before starting the intervention, out of 264 people who participated in the study, 54 people were excluded from the study due to a lack of inclusion criteria and other reasons.Therefore, 210 people were randomly divided into two groups: 105 women receiving the vaginal form and 105 women receiving an oral form of the drug.

2 α
= 0.05, β = 0.20, p 1 = 0.01, p 2 = 0.04, d = 0.04.The women were randomly divided into two groups by a project colleague (randomization was performed using random number table and randomizer software with the ratio of 1:1, meaning one in vaginal group and one in oral dydrogesterone group).One care provider generated the random allocation sequence, enrolled participants, and assigned participants to interventions.The person who assessed outcomes was not aware of the division of people into two treatment groups.The selected samples were entered into the ovulation induction with a long GnRH agonist protocol and fresh ET was done at the cleavage or eight-cell stage, 48 h after oocyte puncture.It should be noted that we have transferred in each cycle a good-quality embryos (Grade A).The first group received 20 mg dydrogesterone tablets twice daily (Duphaston; Abbot Biological B.V.) and the second group received 400 mg natural micronized vaginal progesterone once daily (MVP, Cyclogest; Actavis).All treated patients had no pathology in their initial uterine evaluation.Dydrogesterone or MVP treatment was initiated from the day of ovarian puncture.If the pregnancy test was positive on the 16th day of ET, the drug administration was continued until 12 weeks of gestation and then discontinued.15Demographic and fertility characteristics were recorded of all patients candidates for ART.Patients were compared based on the type of administered progesterone for LPS in the ART cycle and the type of administration, whether oral or vaginal.The primary outcome Comparison of pregnancy outcome in study groups.Pregnancy outcome in the multiple logistic regression analysis in the first stage.
a Data are presented as means ± standard deviation.Student's t test.T A B L E 2Abbreviation: β-hCG, β-human chorionic gonadotropin.aData presented as n (%).χ 2 test.T A B L E 3 a